As others have mentioned, you should expect to retune the ECM. You'll need to adjust the injector "offset" values to match the characteristics of your injectors. If those are set wrong the ECM will get confused trying to figure out the fuel trims and it may suffer the notorious hunting idle problem.
My car is still a 2.8L but I believe the refurb injectors that a shop sent me several years ago came from a 1993-95 3.4L FBody (I didn't confirm with certainty).
To make those injectors work properly the most important thing was to copy the injector offset tables that were in the stock ECM tune for those 3.4L cars. That fixed the idle and I think it was what also fixed a stumble coming off idle.
The files for those cars were posted by somebody on another ECM tuning forum (maybe it was gearhead-efi?).
After that you can start tweaking the BPC value to globally make it richer or leaner.

BTW on a side note, burning chips for the ECM also gives you the ability to tweak timing for an emissions test without it being detectable. They only check the base timing, not the advance added by the ECM.

quote Originally posted by Notorio: OB1 was up to 1996. Hot dog! Retaining the distributor of course, should ET1 Engineer also consider swapping in the ECM 7730 to accrue its several advantages?? Seems like a CA-friendly change since it is invisible and with OB1 they don't plug in.

I recently left California, and I still have to pinch myself to realize that I don't have to worry about these nitpicky emissions inspections ever again.

But while I was there, I thought about doing a 7730 swap. If it's done correctly then the Check Engine light should still work so I don't think that's a problem.
The only problem that I see with it is when the inspector checks your ignition timing. They will short the A-B terminals on the ALDL connector to bypass the ECM's timing advance, then go back to check the base timing against the 10BTDC spec.
The 7730 requires a different procedure. On the 7730 you're supposed to unplug a connector, not short the A-B terminals.
So it won't disable the ECM advance as expected when the inspector tries to check the timing, and you'll fail because of the extra advance.
I'm guessing the CARB computer tells them about the A-B procedure so they'll expect it to be like that.
I don't think there's any good way of telling the inspector about the EST wire without getting yourself into trouble for "tampering" with a 35 year old car.

Now you *could* make a test chip that runs 10BTDC at idle even with the EST connected, but that's an 8degree retard vs stock. That should get you past the timing check, but the "check engine" light won't be blinking as it normally does with A-B shorted. I don't know if the inspector would notice or care about that.


My plan was to build an adapter harness so I could easily swap back to the stock 7170 ECM for emissions test day. That's a little insane since the emissions are probably better with the 7730, but it's California.
I never did the project, it's still on the "to-do" list. Now that I'm out I don't need to worry about testing anymore, but I think I'll still build an adapter harness to start with.

[This message has been edited by armos (edited 12-21-2020).]

[This message has been edited by Mickey_Moose (edited 01-24-2021).]